<?php
/**
 * "Inline" diff renderer.
 *
 * $Horde: framework/Text_Diff/Diff/Renderer/inline.php,v 1.4.10.14 2008/01/04 10:37:27 jan Exp $
 *
 * Copyright 2004-2008 The Horde Project (http://www.horde.org/)
 *
 * See the enclosed file COPYING for license information (LGPL). If you did
 * not receive this file, see http://opensource.org/licenses/lgpl-license.php.
 *
 * @author  Ciprian Popovici
 * @package Text_Diff
 */

/** Text_Diff_Renderer */
require_once 'Text/Diff/Renderer.php';

/**
 * "Inline" diff renderer.
 *
 * This class renders diffs in the Wiki-style "inline" format.
 *
 * @author  Ciprian Popovici
 * @package Text_Diff
 */
class Text_Diff_Renderer_inline extends Text_Diff_Renderer {

	/**
	 * Number of leading context "lines" to preserve.
	 */
	var $_leading_context_lines = 10000;

	/**
	 * Number of trailing context "lines" to preserve.
	 */
	var $_trailing_context_lines = 10000;

	/**
	 * Prefix for inserted text.
	 */
	var $_ins_prefix = '<ins>';

	/**
	 * Suffix for inserted text.
	 */
	var $_ins_suffix = '</ins>';

	/**
	 * Prefix for deleted text.
	 */
	var $_del_prefix = '<del>';

	/**
	 * Suffix for deleted text.
	 */
	var $_del_suffix = '</del>';

	/**
	 * Header for each change block.
	 */
	var $_block_header = '';

	/**
	 * What are we currently splitting on? Used to recurse to show word-level
	 * changes.
	 */
	var $_split_level = 'lines';

	function _blockHeader($xbeg, $xlen, $ybeg, $ylen)
	{
		return $this->_block_header;
	}

	function _startBlock($header)
	{
		return $header;
	}

	function _lines($lines, $prefix = ' ', $encode = true)
	{
		if ($encode) {
			array_walk($lines, array(&$this, '_encode'));
		}

		if ($this->_split_level == 'words') {
			return implode('', $lines);
		} else {
			return implode("\n", $lines) . "\n";
		}
	}

	function _added($lines)
	{
		array_walk($lines, array(&$this, '_encode'));
		$lines[0] = $this->_ins_prefix . $lines[0];
		$lines[count($lines) - 1] .= $this->_ins_suffix;
		return $this->_lines($lines, ' ', false);
	}

	function _deleted($lines, $words = false)
	{
		array_walk($lines, array(&$this, '_encode'));
		$lines[0] = $this->_del_prefix . $lines[0];
		$lines[count($lines) - 1] .= $this->_del_suffix;
		return $this->_lines($lines, ' ', false);
	}

	function _changed($orig, $final)
	{
		/* If we've already split on words, don't try to do so again - just
		 * display. */
		if ($this->_split_level == 'words') {
			$prefix = '';
			while ($orig[0] !== false && $final[0] !== false &&
			substr($orig[0], 0, 1) == ' ' &&
			substr($final[0], 0, 1) == ' ') {
				$prefix .= substr($orig[0], 0, 1);
				$orig[0] = substr($orig[0], 1);
				$final[0] = substr($final[0], 1);
			}
			return $prefix . $this->_deleted($orig) . $this->_added($final);
		}

		$text1 = implode("\n", $orig);
		$text2 = implode("\n", $final);

		/* Non-printing newline marker. */
		$nl = "\0";

		/* We want to split on word boundaries, but we need to
		 * preserve whitespace as well. Therefore we split on words,
		 * but include all blocks of whitespace in the wordlist. */
		$diff = new Text_Diff($this->_splitOnWords($text1, $nl),
		$this->_splitOnWords($text2, $nl));

		/* Get the diff in inline format. */
		$renderer = new Text_Diff_Renderer_inline(array_merge($this->getParams(),
		array('split_level' => 'words')));

		/* Run the diff and get the output. */
		return str_replace($nl, "\n", $renderer->render($diff)) . "\n";
	}

	function _splitOnWords($string, $newlineEscape = "\n")
	{
		// Ignore \0; otherwise the while loop will never finish.
		$string = str_replace("\0", '', $string);

		$words = array();
		$length = strlen($string);
		$pos = 0;

		while ($pos < $length) {
			// Eat a word with any preceding whitespace.
			$spaces = strspn(substr($string, $pos), " \n");
			$nextpos = strcspn(substr($string, $pos + $spaces), " \n");
			$words[] = str_replace("\n", $newlineEscape, substr($string, $pos, $spaces + $nextpos));
			$pos += $spaces + $nextpos;
		}

		return $words;
	}

	function _encode(&$string)
	{
		$string = htmlspecialchars($string);
	}

}
